Serum Creatinine-Cystatin C Based Screening of Sarcopenia in Community Dwelling Older Adults: A Cross-Sectional Analysis.

OBJECTIVES: To compare the discriminative capabilities for the manifestation of sarcopenia or physical frailty between serum creatinine- and cystatin C-derived indices among community-dwelling older adults. DESIGN: Cross-sectional study. SETTING: Primary Care and Community. PARTICIPANTS: We utilized a subset of data from the Frail Elderly in the Sasayama-Tamba Area (FESTA) study, which was initiated in 2015 to gather comprehensive information on various health-related parameters among community-dwelling older individuals (age ≥65 years). MEASUREMENTS: Five serum creatinine-cystatin C based indices including the Sarcopenia Index, the serum creatinine/cystatin C ratio, the disparity between serum cystatin-C-based and creatinine-based estimated GFR, the total body muscle mass index (TBMM), and the prediction equation for skeletal muscle mass index (pSMI) were employed. Sarcopenia and physical frailty were identified based on the Asian Working Group for Sarcopenia criteria and the revised Japanese version of the Cardiovascular Health Study criteria, respectively. The receiver operating characteristic (ROC) and logistic regression analyses were performed to assess the discriminative abilities of these tools. RESULTS: In the analysis of 954 participants, 52 (5.5%) were identified with sarcopenia and 35 (3.7%) with physical frailty. Regarding sarcopenia discrimination, TBMM and pSMI both exhibited area under the curve (AUC) values exceeding 0.8 for both men and women. Concerning the identification of physical frailty, AUC values ranged from 0.61 to 0.77 for males and 0.50 to 0.69 for females. In the multivariate logistic regression analyses, only TBMM and pSMI consistently displayed associations with sarcopenia, irrespective of sex (P<0.001, respectively). On the other hand, no consistent associations were observed between the indices and physical frailty. CONCLUSIONS: This study provides a robust association of a serum creatinine- and cystatin C-derived indices, especially TBMM and pSMI, with sarcopenia among community-dwelling older adults. Conversely, the application of these indices for the screening of physical frailty has its constraints, necessitating further investigation.

Relevance of level IIb neck dissection in patients with papillary thyroid carcinoma.

BACKGROUND: Cervical nodal metastasis is a key prognostic factor in patients with papillary thyroid carcinoma. The role of lymph nodes in papillary thyroid carcinoma management and prognosis remains controversial. METHODS: Level IIb lymph nodes obtained from 44 patients with papillary thyroid carcinoma were histopathologically examined retrospectively. Specimens were classified as ipsilateral or contralateral. The number of dissected nodes and prevalence of level IIb metastasis were compared according to pre-operative clinical nodal stage. RESULTS: In the node-negative neck, the prevalence of contralateral and ipsilateral IIb nodes was 0 out of 20 and 0 out of 3, respectively. In the node-positive neck, the prevalence of contralateral and ipsilateral IIb nodes was 1 out of 13 (7.70 per cent) and 3 out of 41 (7.32 per cent), respectively. Clinically determined and pathologically confirmed level IIb node negativity were significantly associated. Thirty-four patients (77.3 per cent) developed accessory nerve complications from level IIb dissection. CONCLUSION: Level IIb neck dissection for papillary thyroid carcinoma may be required if pre-operative examination reveals multilevel, level IIa or suspicious level IIb metastasis.

Therapeutic results of the modified cadenat procedure for acromioclavicular joint separations compared with the modified dewar procedure / Resultados terapéuticos del procedimiento de cadenat modificado para las separaciones de la articulación acromioclavicular en comparación con el procedimiento de dewar modificado

AIM AND BACKGROUND: The surgical treatment for acromioclavicular joint dislocations is recommended for Rockwood's classification types 4, 5 and 6. In this study, we evaluate the therapeutic results of the modified Cadenat procedure on type 5 acromioclavicular joint dislocation, and report on a comparative study of the modified Dewar procedure also on type 5 acromioclavicular joint dislocation. SUBJECTS AND METHODS: The modified Cadenat procedure was performed on 73 patients (66 males and 7 females, group C). The mean age at the time of the surgery was 35.4 years. On the other hand, the modified Dewar procedure was performed on 55 patients (51 males and 4 females, group D). The mean age at the time of the surgery was 34.5 years. RESULTS: The mean therapeutic results were 28.2 points in group C and 27.3 in group D according to the UCLA scoring system. In group C, the subluxation that represented less than 5 mm superior translation of the clavicle, occurred only in 18 of 73 patients. Meanwhile, in group D, the subluxation that represented less than 5 mm, occurred only in 14; that which represented 5 to 10 mm was in seven patients, and the complete dislocation occurred in three patients. Also, the occurrence ofosteoarthritic changes in the acromioclavicular joint was nine patients in group C and 20 in group D, respectively. CONCLUSION: The modified Cadenat procedure could provide satisfactory therapeutic results and avoid postoperative failure of reduction compared to the modified Dewar procedure. However, the modified Cadenat procedure does not aim to restore the anatomical coracoclavicular ligaments. It is believed that anatomic restoration ofboth coracoclavicular ligaments could best restore the function ofthe acromioclavicular joint.

OBJETIVO Y ANTECEDENTES: El tratamiento quirúrgico para las dislocaciones de la articulación acromioclavicular se recomienda para los tipos 4, 5, y 6 de la clasificación de Rookwood. En este estudio, se evalúan los resultados terapéuticos del procedimiento de Cadenat modificado en dislocación de la articulación acromioclavicular de tipo 5, y también se informa sobre el estudio comparativo con el procedimiento de Dewar modificado practicado sobre el tipo 5 de dislocación de la articulación acromioclavicular. SUJETOS Y MÉTODOS: El procedimiento de Cadenat modificado se realizó en 73 pacientes (66 varones y 7 hembras, grupo C). La edad promedio en el momento de la cirugía era 35.4 años. Por otro lado, el procedimiento de Dewar modificado se realizó en 55 pacientes (51 varones y 4 hembras, grupo D). La edad promedio en el momento de la cirugía era 34.5 años. RESULTADOS: Los resultados terapéuticos promedio fueron 28.2 puntos en el grupo C y 27.3 en el grupo D de acuerdo con el sistema de puntuación UCLA. En el grupo C, la subluxación que representó menos de 5 mm de traslación superior de la clavícula, sólo ocurrió en 18 de 73 pacientes. Entretanto, en el grupo D, la subluxación que representó menos de 5 mm, sólo ocurrió en 14; la subluxación que representó de 5 a 10 mm ocurrió en siete pacientes; yla dislocación completa ocurrió en tres pacientes. También, la ocurrencia de cambios osteoartríticos en la articulación acromioclavicular fue de nueve pacientes en el grupo C y 20 en el grupo D, respectivamente. CONCLUSIÓN: El procedimiento de Cadenat modificado podría proporcionar resultados terapéuticos satisfactorios, y podría evitar el fracaso postoperatorio de la reducción en comparación con el procedimiento de Dewar modificado. Sin embargo, el procedimiento de Cadenat modificado no esta dirigido a restaurar los ligamentos coracoclaviculares anatómicas. Se entiende que la restauración anatómica de ambos ligamentos coracoclaviculares pudiera restaurar mejor la función de la articulación acromioclavicular.

A novel tumor-derived SGOL1 variant causes abnormal mitosis and unstable chromatid cohesion.

Mitosis is the most conspicuous cell cycle phase, because it is the phase in which the dynamic physical distributions of cellular components into the two daughter cells occur. The separation of sister chromatids is especially important during mitosis, because of the extreme accuracy required for distribution to the next generation of cells. Shugoshin-like 1 (SGOL1) is a key protein in protecting sister chromatids from precocious separation. We have reported finding that chromosome instability is more likely in SGOL1-downregulated colorectal cancers, but it is still unknown whether there is an association between cancer and SGOL1 transcript variation. Here, we identified a novel SGOL1 variant, SGOL1-P1, in human colon cancer. The SGOL1-P1 transcript contains an exon-skip of exon 3 that results in a stop codon occurring within exon 4. Overexpression of SGOL1-P1 in HCT116 cells resulted in an increased number of cells with aberrant chromosome alignment, precociously separated chromatids and delayed mitotic progression, occasionally followed by inaccurate distribution of the chromosomes. These phenotypes, observed when SGOL1-P1 was present, were also observed very frequently in SGOL1-knockdown cells. Furthermore, the overexpression of SGOL1-P1 inhibited the localization of endogenous SGOL1 and cohesin subunit RAD21/SCC1 to the centromere. These results suggest that SGOL1-P1 may function as a negative factor to native SGOL1, and that abundant expression of SGOL1-P1 may be responsible for chromosomal instability.

A screen for potential ferredoxin electron transfer partners uncovers new, redox dependent interactions.

Ferredoxin (Fd) is the primary soluble acceptor at the end of the photosynthetic electron transport chain, and is known to directly transfer electrons to a wide range of proteins for use in metabolism and regulatory processes. We have conducted a screen to identify new putative Fd interaction partners in the cyanobacteria Synechocystis sp. PCC 6803 using Fd-chromatography in combination with MALDI-TOF mass spectrometry. Many novel interactions were detected, including several redox enzymes, which are now candidates for further experiments to investigate electron transfer with Fd. In addition, some proteins with regulatory activity related to photosynthesis were identified. We cloned and expressed one such protein, known as RpaA, which is a specific regulator of energy transfer between phycobilisomes and PSI. Using the recombinant protein we confirmed direct interaction with Fd, and discovered that this was dependent on redox state. The screen for putative Fd-binding proteins was repeated, comparing oxidizing and reducing conditions, identifying many proteins whose interaction with Fd is redox dependent. These include several additional signaling molecules, among them the LexA repressor, Ycf53 and NII, which are all involved in interpreting the redox state of the cell.

Therapeutic results of the modified Cadenat procedure for acromioclavicular joint separations compared with the modified Dewar procedure.

AIM AND BACKGROUND: The surgical treatment for acromioclavicular joint dislocations is recommended for Rockwood's classification types 4, 5 and 6. In this study we evaluate the therapeutic results of the modified Cadenat procedure on type 5 acromioclavicular joint dislocation, and report on a comparative study of the modified Dewar procedure also on type 5 acromioclavicular joint dislocation. SUBJECTS AND METHODS: The modified Cadenat procedure was performed on 73 patients (66 males and 7 females, group C). The mean age at the time of the surgery was 35.4 years. On the other hand, the modified Dewar procedure was performed on 55 patients (51 males and 4 females, group D). The mean age at the time of the surgery was 34.5 years. RESULTS: The mean therapeutic results were 28.2 points in group C and 27.3 in group D according to the UCLA scoring system. In group C, the subluxation that represented less than 5 mm superior translation of the clavicle, occurred only in 18 of 73 patients. Meanwhile, in group D, the subluxation that represented less than 5 mm, occurred only in 14; that which represented 5 to 10 mm was in seven patients, and the complete dislocation occurred in three patients. Also, the occurrence of osteoarthritic changes in the acromioclavicular joint was nine patients in group C and 20 in group D, respectively. CONCLUSION: The modified Cadenat procedure could provide satisfactory therapeutic results and avoid postoperative failure of reduction compared to the modified Dewar procedure. However the modified Cadenat procedure does not aim to restore the anatomical coracoclavicular ligaments. It is believed that anatomic restoration of both coracoclavicular ligaments could best restore the function of the acromioclavicular joint.

Human Sgo1 downregulation leads to chromosomal instability in colorectal cancer.

BACKGROUND AND AIMS: Chromosomal instability (CIN) is recognised as a hallmark of cancer and is caused by a spindle assembly checkpoint disorder or chromosome mis-segregation during mitosis. Although the recent identification of human shugoshin (hSgo1), an important player in proper chromosome segregation, has suggested the involvement of hSgo1 in colorectal tumourigenesis, little is known about how it is involved. The aim of this study was to obtain information about the status of hSgo1 in human colorectal cancer. METHOD AND RESULTS: Among the 46 colorectal cancer cases, hSgo1 mRNA expression was decreased in the tumour tissue in comparison with the corresponding normal tissue (p = 0.032). Human Sgo1-downregulated tumours (tumour to normal mucosa ratio<0.5) had preferential location on the left side large bowel rather than on the right side (p = 0.012), and a higher variation of centromere numbers revealed by fluorescence in situ hybridisation (FISH). To assess the effects of hSgo1 downregulation, hSgo1 knockdown was performed by transfecting the diploid HCT116 cell line with a short hairpin RNA expression vector. hSgo1 knockdown cells proliferated slowly because of both G(2)/M arrest and apoptosis (p<0.001), and markers of CIN in the form of aneuploidy (p<0.001) and micronuclei (p<0.005) were later observed in hSgo1 knockdown cells. Increased centrosome amplification (p<0.05), the presence of binucleated cells and mitotic catastrophes were also noted in hSgo1 knockdown cells. CONCLUSIONS: These findings suggest that hSgo1-downregulated colorectal cancers have a clinicopathological character of CIN, and hSgo1 downregulation leads to CIN in colorectal cancer cells.

Induction of centrosome amplification and chromosome instability in p53-deficient lung cancer cells exposed to benzo[a]pyrene diol epoxide (B[a]PDE).

Benzo[a]pyrene diol epoxide (B[a]PDE), the ultimate carcinogenic metabolite of benzo[a] pyrene, has been implicated in the mutagenesis of the p53 gene involved in smoking-associated lung cancer. To further understand the role of B[a]PDE in lung tumour progression, we investigated its effect on the numerical integrity of centrosomes and chromosome stability in lung cancer cells lacking p53. Exposure of p53-deficient H1299 lung cancer cells to B[a]PDE resulted in S-phase arrest, leading to abnormal centrosome amplification. Analysis of H1299 cells stably expressing fluorescence-tagged centrin (a known centriolar marker) revealed that the centrosome amplification was primarily attributable to excessive centrosome duplication rather than to centriole splitting. Forced expression of POLK DNA polymerase, which has the ability to bypass B[a]PDE-guanine lesions in an error-free manner, suppressed the B[a]PDE-induced centrosome amplification. Fluorescence in situ hybridization analyses with probes specific for chromosomes 2, 3, and 16 revealed that B[a]PDE exposure also led to chromosome instability, which was likely to have resulted from centrosome amplification. We extended these findings to primary lung carcinomas containing non-functional p53, and found a strong association between centrosome amplification and a high level of B[a]PDE-DNA accumulation. Therefore B[a]PDE contributes to neoplasia by inducing centrosome amplification and consequent chromosome destabilization as well as its mutagenic activity.

Direct evidence for the role of centrosomally localized p53 in the regulation of centrosome duplication.

Abnormal amplification of centrosomes is the major cause of mitotic defects and chromosome instability in cancer cells. Centrosomes duplicate once in each cell cycle, and abrogation of the regulatory mechanism underlying centrosome duplication leads to centrosome amplification. p53 tumor suppressor protein is involved in the regulation of centrosome duplication: loss of p53 as well as expression of certain p53 mutants result in deregulated centrosome duplication and centrosome amplification. p53 at least in part depends on its transactivation function to control centrosome duplication, primarily via upregulation of p21 cyclin-dependent kinase (CDK) inhibitor, which prevents untimely activation of CDK2/cyclin E, a key initiator of centrosome duplication. However, numerous studies have shown the presence of p53 at centrosomes, yet the role of the centrosomally localized p53 in the regulation of centrosome duplication had been enigmatic. Here, we comparatively examined wild-type p53 and p53 mutants that are transactivation(+)/centrosome-binding(-), transactivation(-)/centrosome-binding(+) and transactivation(-)/centrosome-binding(-) for their abilities to control centrosome duplication. We found that the transactivation(+)/centrosome-binding(-) and transactivation(-)/centrosome-binding(+) mutants suppress centrosome duplication only partially compared with wild-type p53. Moreover, the transactivation(-)/centrosome-binding(-) mutant almost completely lost the ability to suppress centrosome duplication. These observations provide direct evidence for the centrosomally localized p53 to participate in the regulation of centrosome duplication in a manner independent of its transactivation function in addition to its transactivation-dependent regulation of centrosome duplication.

Greater development of 1,2-dimethylhydrazine-induced colon cancer in a rat model of type 2 diabetes mellitus.

Several clinical cohort and case-control studies have suggested a link between diabetes and colon cancer. Otsuka Long-Evans Tokushima Fat (OLETF) rats spontaneously develop type 2 diabetes mellitus and Long-Evans Tokushima Otsuka (LETO) rats are non-diabetic. The relationship between type 2 diabetes mellitus and colon cancer was examined in these rats. The carcinogen 1,2-dimethylhydrazine was administered subcutaneously once weekly for 10 weeks, and the animals were killed and necropsied in week 29. All OLETF rats and 80% of the LETO rats developed cancer. The number of colon cancers per rat was significantly greater in the diabetic than in the non-diabetic rats. Although the tumours tended to be larger in diabetic rats, the difference was not statistically significant. No significant differences were observed in the depth of invasion or histological type of cancer in the two groups. Type 2 diabetes mellitus may enhance the generation and growth of colon cancer.

A novel STK11 germline mutation in two siblings with Peutz-Jeghers syndrome complicated by primary gastric cancer.

Patients with Peutz-Jeghers syndrome (PJS) are known to be at risk of gastric cancer (GC), and the STK11 gene is a susceptibility gene for PJS. However, as no cases of PJS with GC in which a STK11 germline mutation has been identified have ever been reported and other susceptibility genes have also been suggested to be involved in PJS, the relation between STK11 germline mutations and GC in PJS is still unknown. In this study, we used sequencing analysis to investigate the STK11, CDH1, and TP53 loci for a germline mutation in two siblings with PJS with primary GC. A novel type of the STK11 germline mutation, c.890delG, encoding a truncated protein (p.Arg297fsX38) was identified, but no germline mutations of the CDH1 and TP53 genes were detected. No inactivation of the wild-type allele by somatic mutation or chromosomal deletion or hypermethylation at the 5'-CpG site of STK11 was detected in the GC. This is the first report of a STK11 germline mutation in a PJS patient with GC and should contribute to establishing correlations between the STK11 germline mutations and GC in PJS patients.

Autologous blood transfusion in total hip arthroplasty.

PURPOSE: To determine the possibility of avoiding homologous blood transfusion during total hip arthroplasty, and to clarify the problems associated with autologous blood transfusion. METHODS: A total of 253 patients received autologous blood transfusion during total hip arthroplasty between April 1990 and December 2000. Patients were assessed for the volume of haemorrhage during surgery, possibility of avoidance of homologous blood transfusion, and the disposal of autologous blood. RESULTS: There were no significant differences in the mean volume of haemorrhage among different underlying diseases. The mean total volume of haemorrhage was 2039 (standard deviation, 992) ml in revision surgery and 1673 (717.3) ml in primary surgery (p<0.05). The rate of avoidance of homologous blood transfusion was 75% among patients who underwent primary surgery, and 61% among those who underwent revision surgery. The rate was 95% in cases in which a combination of preoperative blood pooling and intra-operative recovery was used, 49% in cases where the preoperative blood pooling system alone was used, and 42% in those in which the intra-operative recovery system alone was employed. The autologous blood had to be disposed of in 3 (1%) cases, all of which were revision procedures with replacement of the polyethylene liner alone. CONCLUSION: Combined use of the preoperative blood pooling and intra-operative recovery systems is effective for avoiding homologous blood transfusion.

OGG1 protein suppresses G:C-->T:A mutation in a shuttle vector containing 8-hydroxyguanine in human cells.

8-Hydroxyguanine (8-OHG) is an oxidatively damaged mutagenic base which causes G:C-->T:A transversions in DNA. OGG1 was cloned as a human gene encoding a DNA glycosylase that specifically excises 8-OHG from DNA in vitro. However, it was not clear whether OGG1 protein suppresses G:C-->T:A transversions caused by 8-OHG in human cells in vivo. In the present study we have examined the ability of OGG1 protein to suppress G:C-->T:A transversions caused by 8-OHG in human cells by bacterial suppressor tRNA (supF) forward mutation assay using a shuttle vector DNA, pMY189. Introduction of a single 8-OHG residue at position 159 of the supF gene in plasmid pMY189 resulted in a 130-fold increase in mutation frequency compared with untreated plasmid pMY189 after replication in the NCI-H1299 human lung cancer cell line. G:C-->T:A transversions at position 159 were detected in >90% of the supF mutants from the 8-OHG-containing plasmid. The mutation frequency of the 8-OHG-containing plasmid was significantly reduced by overexpression of OGG1 protein in NCI-H1299 cells and, in particular, the occurrence of G:C-->T:A transversion at position 159 in the supF gene was suppressed. Furthermore, frequencies and spectra of mutations of the untreated pMY189 plasmid did not differ significantly with overexpression of OGG1 protein. These results indicate that OGG1 protein has the ability to suppress G:C-->T:A transversions caused by 8-OHG in human cells in vivo.

The OGG1 gene encodes a repair enzyme for oxidatively damaged DNA and is involved in human carcinogenesis.

8-Hydroxyguanine (oh8G) is a major base lesion produced by reactive oxygen species. oh8G in DNA causes G:C to T:A transversions and, thus, could be responsible for mutations that lead to carcinogenesis. A human DNA glycosylase/AP lyase encoded by the OGG1 gene has an activity to remove directly oh8G from DNA, and suppresses the mutagenic effect of oh8G. OGG1 protein has a helix-hairpin-helix-GPD motif as a domain for both DNA binding and catalysis, a nuclear localization signal, and a mitochondria targeting signal. Among multiple OGG1 isoforms, OGG1-type la is expressed predominantly in human cells and repairs chromosomal DNA in the nucleus. Inactivation of the OGG1 gene in yeast and mice leads to elevated spontaneous mutation frequency in the cells. The human OGG1 gene maps to chromosome 3p26.2, and allelic deletions of this region occur frequently in a variety of human cancers. Moreover, the OGG1 gene is somatically mutated in some cancer cells and is highly polymorphic among human populations. Repair activities of some mutated and polymorphic OGG1 proteins are lower than those of wild-type OGG1-type la-Ser326 protein and, thus, could be involved in human carcinogenesis.

Germline p53 mutation in a patient with multiple primary cancers.

We report a case of multiple primary cancers having a germline missense mutation of the p53 gene. The patient was a Japanese female and had a history of five different types of cancers. PCR/direct sequencing analysis revealed the presence of a nucleotide substitution, AGC (Ser) to AGG (Arg), at codon 106 of the p53 gene in DNA from non-cancerous breast tissue. This is the first case of germline p53 mutation at codon 106, and could contribute to establishing correlations between the types and locations of germline p53 mutations and their phenotypical consequences.

Cyclooxygenase-2 does not mediate late preconditioning induced by activation of adenosine A1 or A3 receptors.

Recent studies have demonstrated that the adenosine A1 receptor agonist 2-chloro-N6-cyclopentyladenosine (CCPA) and the adenosine A3 receptor agonist N6-(3-iodobenzyl)adenosine-5'-N-methyluronamide (IB-MECA) produce a delayed phase of protection against infarction similar to the late phase of ischemic preconditioning (PC). However, the mechanism for adenosine A1 or A3 receptor-induced late PC remains unknown. The goal of this study was to determine whether the delayed cardioprotective effects of adenosine A1 or A3 receptors are mediated by cyclooxygenase-2 (COX-2), which is an obligatory mediator of ischemic PC. We found that COX-2 protein expression (Western blotting) did not increase 24 h after the administration of either CCPA (100 microg/kg iv) or IB-MECA (300 microg/kg iv) compared with controls. To probe the role of constitutive COX-2 expression, conscious rabbits were subjected to 30-min coronary occlusion followed by 72-h reperfusion. Twenty-four hours before the occlusion, the rabbits were pretreated with CCPA (100 microg/kg iv) or IB-MECA (300 microg/kg iv). Both CCPA and IB-MECA resulted in a marked (approximately 47%) reduction in infarct size vs. controls [36.2 +/- 4.0% of the risk region (n = 9), 31.2 +/- 4.7% (n = 9), and 59.5 +/- 3.8% (n = 9), respectively; P < 0.05], similar to that induced by the late phase of ischemic PC [31.8 +/- 3.2% (n = 9)]. The selective COX-2 inhibitor N-(2-[cyclohexyloxy]4-nitrophenyl)methanesulfonamide (NS-398, 5 mg/kg), which abolished the protective effect of ischemic late PC, failed to block the protection of either CCPA or IB-MECA, indicating that COX-2 does not mediate the delayed protection of either CCPA or IB-MECA [CCPA + NS-398, 29.1 +/- 3.4% (n = 7); IB-MECA + NS-398, 34.9 +/- 2.9% (n = 8)]. NS-398 in itself did not affect infarct size [54.9 +/- 3.7% (n = 9)]. Taken together, these results demonstrate that, in contrast to ischemia-induced late PC, the mechanisms of adenosine A1 or A3 receptor-induced late PC is independent of COX-2.

Enhancement of OGG1 protein AP lyase activity by increase of APEX protein.

8-Hydroxyguanine (oh(8)G) is a major form of oxidative DNA damage produced by reactive oxygen species (ROS). The human OGG1 gene encodes a DNA glycosylase that excises oh(8)G from double-stranded DNA. In this study, we investigated a mode of interaction between OGG1 and APEX proteins in the repair of oh(8)G under oxidative stresses. DNA cleavage assay using oh(8)G-containing oligonucleotides showed that the phosphodiester bond on the 3'-side of oh(8)G was cleaved by the AP lyase activity of GST-OGG1 protein and the phosphodiester bond on the 5'-side of oh(8)G was cleaved by the DNA 3'-repair diesterase activity of APEX protein. Gel mobility shift assay showed that the complex of GST-OGG1 protein and oh(8)G-containing oligonucleotides mostly changed into the complex of APEX protein and oligonucleotides by addition of APEX protein into the reaction mixture. We next analyzed alterations in the amount of 8-hydroxydeoxyguanosine (oh(8)dG) in DNA and the levels of OGG1 and APEX expression in HeLa S3 cells treated with 2mM hypochlorous acid, a kind of ROS. An approximately four-fold increase in the amount of oh(8)G was detected by the HPLC-ECD method. Reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot analyses indicated that the level of APEX expression increased approximately four-fold, whereas the level of OGG1 expression was unchanged. However, in the DNA cleavage assay, the AP lyase activity of GST-OGG1 protein was significantly increased in the presence of a molar excess of APEX protein. These results indicate that, under severe oxidative stresses, OGG1 mRNA is not induced and the amount of OGG1 protein is not remarkably increased, but the activity of OGG1 protein is enhanced by the increase of APEX protein in the cells.

Somatic mutations and single nucleotide polymorphisms of base excision repair genes involved in the repair of 8-hydroxyguanine in damaged DNA.

To elucidate the involvement of 8-hydroxyguanine (oh(8)G) repair genes in human lung carcinogenesis, 47 lung cancer cell lines and 55 primary lung cancers were examined for somatic mutations and genetic polymorphisms in all coding exons of the MYH and APEX genes, and exon 8 of the OGG1 gene by polymerase chain reaction-single strand conformation polymorphism analysis. In the MYH gene, one missense mutation was detected in a cell line, NCI-H157, whereas no mutations were detected in primary cancers. There were no mutations in the APEX and OGG1 genes in the cell lines or primary cancers. Ten single nucleotide polymorphisms (SNPs) were identified, and seven of them were accompanied by amino acid substitutions. Differences in the oh(8)G repair activities of MYH, APEX and OGG1 proteins due to somatic mutations and SNPs can be involved in human carcinogenesis.

Catheter-delivered in vivo gene transfer into rat myocardium using the fusigenic liposomal mediated method.

We compared the efficacy of four different in vivo hemagglutinating virus of Japan (HVJ)-liposome gene transfer methods, i.e., direct myocardial injection (i.m.), injection into the left ventricular cavity (LV), infusion at the level of the coronary cusps (CI), or injection into the left ventricular cavity with a balloon catheter blocking aortic flow (LV+B) to transfer beta-galactosidase, FlTC-labeled oligodeoxynucleotide (ODN), and/or luciferase genes into the rat heart. I.m. caused highly efficient gene transfer in the limited area around the injection site, which suggests that i.m. may be a suitable method for targeted treatment of focal lesion. In the LV+B group, all rats had myocardial beta-galactosidase staining and fluorescence of FITC-labeled ODN in the nuclei of cardiac myocytes around the coronary arteries and the vasa vasorum, and some transfected myocytes were observed in the middle of the myocardium without any evidence of injury. In contrast, in the CI group, only half of the animals had myocardial expression of beta-galactosidase. In contrast, fluorescence or luciferase activity was present throughout the left ventricle in the LV+B group. However, the percentage of myocytes that exhibited fluorescence was less than 1% of the total ventricular myocyte population and luciferase activity in the LV+B group was 1.6% of that in the i.m. group. No evidence of luciferase expression was observed in brain, lung, liver, kidney, or testis in either the i.m. or LV+B group. These results suggest that HVJ-liposome gene transfer into the myocardium through the coronary arteries using a balloon-catheter technique is safe and has the potential for causing widespread transgene expression with organ-specificity, although the efficiency of gene transfer should be improved.